A power branching transmission, in particular for a working machine such as a wheel loader, is known from DE 10 2007 047 194 A1 and is formed with a hydrostatic and a mechanical power branch. The power branches are added by a summation gear system, a reversing transmission being connected upstream from the summation gear system and a gearshift transmission being connected downstream therefrom.
By virtue of the power branching transmission, in each case two driving ranges for forward driving and for reversing can be obtained, within which a transmission ratio of the power branching transmission can be varied continuously by means of a hydrostatic device. The driving ranges can be changed by disengaging an engaged shifting element and engaging a disengaged shifting element.
Disadvantageously, a shifting element provided for obtaining a second driving range of the power branching transmission is arranged on a hydrostatic shaft of the hydrostatic device, and because of this to connect the hydrostatic shaft to a mechanical power branch involves complex design. Among other things this results from the fact that to dampen vibrations, the hydrostatic device is usually mounted by way of an elastic rubber mount, and therefore, in the connection area between the hydrostatic device and the mechanical power branch, an axial offset that varies during operation has to be compensated by a connection device of appropriately articulated design. Without additional design measures, however, the result of this constant compensation, in turn, is that in the area of the shifting element arranged on the hydrostatic shaft vibrations are induced to an undesired extent and the tendency to wobble increases.
Moreover, due to the arrangement of the shifting element on the hydrostatic shaft the power branching transmission takes up considerable fitting space since the two hydrostatic shafts of the hydrostatic device have to be arranged a certain distance apart from one another in order to be able to provide the space necessary for fitting the shifting element on the hydrostatic shaft.